Overall Equipment Effectiveness (OEE)

What is Overall Equipment Effectiveness?

Overall Equipment Effectiveness (OEE) is a comprehensive productivity metric used in Facilities Management Services. OEE is used throughout the manufacturing process to assess the productivity of equipment. OEE combines availability, performance, and quality measures to provide insight into how effectively equipment is being utilized. Plant floor metrics such as OEE are crucial for tracking progress, pinpointing areas of reduced output, and improving the capacity of machines and processes within a facility to operate effectively.

How OEE is Calculated

To run a calculation for determining OEE, you must first determine the availability, performance, and quality scores. These three factors are the fundamental components for gathering an accurate OEE measurement.

Availability 

This metric represents the ratio of run time divided by planned production time, written as [A = run time / planned production time].

For instance, a production line at a shoe factory is expected to run for three 8-hour shifts, for a total planned run time of 24 hours. During this production cycle, the line has to go down a few times that ultimately reduces the actual run time to 19.5 hours. Calculating for performance, the lead operator would get this result: 19.5 / 24 for an availability score of 0.812.

Performance

This measurement indicates the ideal time to produce a unit (cycle time) multiplied by the total number of units produced, with the result divided by the actual run time. The equation looks like this: [P = (ideal cycle time x total units produced) / actual run time].

For example, the shoe factory production crew determined that the ideal cycle time to produce one shoe is 1 minute. The line experienced 19.5 hours of total run time or 1,170 minutes and produced 1000 units during the run. To get the performance score, the equation would look like this: (1 x 1000) / 1,170, for a performance score of 0.854.

Quality 

Production quality expresses the ratio of good units to total produced units. Good units indicate products that didn’t require rework or disposal. The equation for this measurement is simple. [Q = good units / total units produced]

For instance, the shoe factory makes 50,000 shoes during a production cycle. 1,700 of the shoes produced require rework, giving the line 48,300 good shoes out of 50,000. When calculated, we get this result. 48,300 / 50,000 for a 0.966 quality score.

OEE calculation

OEE calculation is represented by the availability score times the performance score times the quality score. When calculating the overall equipment effectiveness metric, the equation appears as follows:

[OEE = A x P x Q]

Using the examples above, the production team can calculate OEE.

[OEE = 0.812 x 0.854 x 0.966; OEE = 0.669]

Some facilities use OEE calculation as a percentage of ideal equipment effectiveness. In this case, you’d simply multiply the results by 100, giving you a 66.9% OEE rating.

Practical Ways That Overall Equipment Effectiveness (OEE) is Used

Facilities management services and plants use overall equipment effectiveness for a wide variety of purposes. These are a few of the most common ways that facilities calculate OEE and utilize their OEE calculation for measuring manufacturing productivity and truly productive manufacturing time throughout the manufacturing process.

Identifying Areas of Improvement

Breaking OEE down into its most fundamental components enables facilities to pinpoint specific issues. Monitoring for OEE can reveal a number of insufficiencies such as excess unplanned downtime, production slow-downs, and high quality-defect counts.

Performance Tracking

Monitoring OEE and its components over time gives companies the ability to evaluate the impact of manufacturing process modifications, maintenance activities, and other changes made in an organization’s continuous improvement efforts.

Benchmarking

By comparing the OEE calculation between different equipment and shifts, facilities can determine baselines for acceptable and optimal production effectiveness. They can use these benchmarks to set realistic real-time production target standards while working to improve manufacturing processes and asset performance.

Maintenance Scheduling

The OEE availability measurement can get a finger on the pulse of downtime activities and pinpoint practical inefficiencies. Low availability indicates the need for process improvements, often pointing to poor maintenance scheduling practices and slow setup processes.

A Practical Example

For instance, a facility manager in a packaging plant might use OEE to evaluate the effectiveness of a new automated packing line. If the OEE score is lower than expected, they can investigate where the issue might lie. A low availability can indicate frequent breakdowns. Low performance might point to slow operation speeds and a low quality score could reveal a large number of packaging errors.

Ways to Improve OEE

While a world-class OEE score is the goal, there are times when a higher-than-ideal OEE indicates issues. Running equipment at their highest settings to attain an acceptable rating could lead to equipment stress and future failures. Consider these practices to optimize your OEE without overextending that capacity of your assets.

• Preventive Maintenance: Regular maintenance can prevent breakdowns and unnecessary equipment stops to improve equipment availability.
• Training: Ensure that operators understand the equipment and know how to get the best results from it. Thorough training can improve both the performance and quality measurements.
• Process Optimization: A streamlined manufacturing process and reduced changeover times can enhance equipment performance.
• Quality Control: Robust quality control measures can significantly reduce the rate of defects and rework, improving the quality score.
• Equipment Upgrades: Investing in newer, more reliable, and faster equipment can improve all three OEE factors as well as addressing underlying issues that impact other manufacturing metrics.

A good example would be a facility that implements a sensor-based monitoring system. Using a computerized maintenance management software (CMMS) system or enterprise asset management (EAM) platform, the facility is able to gather data in real time and employ advanced analytics to anticipate equipment failures.

Overall Equipment Effectiveness OEE in Conclusion

OEE is a critical metric used to indicate how close a facility is to attaining perfect production results, measuring equipment availability and performance, as well as product quality. Scheduling regular preventive maintenance and employing robust process and quality control measures enables the company to maintain a balanced OEE and optimize all production and maintenance metrics.

A powerful CMMS, EAM, or facility maintenance management platform like ServiceChannel is an ideal tool for tracking OEE measurements and gathering data to improve all maintenance metrics. Contact ServiceChannel today and explore a world of maintenance management options for your organization.